1. Field of the Invention
The keyboard of a musical instrument is provided with two sets of landmarks to guide the playing of music written with different notations. The apparatus comprises electronic switching circuitry for selecting different musical scales and for actuating different key signatures for the different scales.
2. Description of the Prior Art
The musical keyboard is a heritage of the slow historical development of music itself. The traditional keyboard, like the traditional musical notation, is structured so as to facilitate performance of music in the diatonic key of C major. For learning and performing keyboard music, it has been truly helpful to have a keyboard whose structure conforms to our system of music notation. However, it has been apparent for some time that music--its enjoyment, performance, and composition,--are unnecessarily hindered by the traditional system of notation and its associated keyboard.
The traditional way of writing music, used by Guido of Arezzo as early as the eleventh century, is to position symbols on a staff consisting of horizontal lines. The seven tones of the diatonic scale are now represented by notes on the lines and spaces of a five-line staff. Interspersed tones of the chromatic pentatone are referred to the basic notes of the diatonic scale by means of sharp or flat symbols which serve as tone corrections to the basic diatonic tones. Thus a chromatic tone intermediate to the C and D tone is represented by C.music-sharp. or D.music-flat..
As early as the fifteenth century, keyboard instruments have played the diatonic scale on the front digitals of the keyboard and tones of the chromatic pentatone on back digitals. At that time it was very helpful to have a keyboard on which the wide front digitals played the most commonly-used tones in the key of C. And it is a considerable advantage to have a system of notation embodying those musical intervals that are most naturally sung and most easily identified. The major mode of the diatonic scale starts with the C tone, played on a C front digital. The succeeding D,E,F,G,A,B tones are played on the succeeding D,E,F,G,A,B front digitals.
For a diatonic musical composition to be written without the use of sharp or flat symbols, it must be written in the key of C. Such a restriction severely limits the choice of a modern composer, for he probably wants to base his composition on a tonic above or below the C tone. This is no problem for musical instruments having pitch changers, but many musical instruments do not have pitch changers. So composers and their publishers resort to a rather unsatisfactory method for specifying the absolute pitch of their diatonic scale; they start the major mode of their diatonic scale on some other note than C. This method requires that one or more of the seven basic diatonic tones be corrected by means of a sharp or flat symbol. The composer finds it convenient to specify the diatonic tone corrections by a key signature that is placed at the front of each line of written music. Key signatures greatly reduce the effort needed to make the diatonic tone corrections.
In the case of a keyboard player, the diatonic tone corrections require playing of the back digitals. This detracts from the former virtue of the traditional keyboard, of providing wide front digitals for the most commonly used tones. Furthermore, after learning to play a musical composition in one key, a keyboard musician finds that playing the composition in a different key requires quite different fingering. Inexperienced keyboard players have difficulty remembering and playing all the sharps or flats called for in the diatonic key signatures.
To alleviate these difficulties, a keyboard instrument can be provided with a device to physically actuate the tone corrections specified in the key signature. Such a device, which I call a key signature actuator, was disclosed by Martin Philipps in 1886 (U.S Pat. Nos. 354,733 and 519,071). If, for example, the device was set for a key signature with one sharp, then the F front digital would play not the F tone, but the F.music-sharp. tone instead, as called out in the key signature. This mechanical type of key signature actuator has not been widely used because of its complexity and expense.
Electrical versions of a key signature actuator have been described by Cornelius in U.S. Pat. No. 2,484,930 and by myself in U.S. Pat. No. 3,986,422. These key signature actuators provide two extra back digitals per octave span (F.music-flat. and B.music-sharp.). The F.music-flat. back digital serves to play the F natural tone when the F front digital is playing the F.music-sharp. tone. The B.music-sharp. back digital serves to play the B natural tone when the B front digital is playing the B.music-flat. tone.
Including these two extra back digitals, my keyboards have seven back digitals and seven front digitals per octave span, the back digitals alternating regularly with the front digitals throughout the keyboard. Seven consecutive front digitals play the diatonic scale. Also, in my earlier invention, seven consecutive back digitals play a diatonic scale based half an octave higher (or lower), and positioned half an octave higher (or lower) on the keyboard.
Key signature actuators such as these greatly reduce the difficulty of playing music, because the musician need not constantly remember the sharps or flats called out in the key signature. The mechanical difficulty of playing in other keys than C is also avoided, because all the most frequently used tones are now played entirely on the wide front digitals of the keyboard. Furthermore, once a musical composition has been learned in one key it can be played in any other key with exactly the same fingering.
It happens that this even keyboard construction for an improved diatonic key signature actuator is also suitable for playing music in improved notations. For example, the front digitals of the keyboard may be connected to play a whole-tone scale, with the back digitals playing the whole-tone scale a semitone higher (or lower). In this condition, any chord may be played at six pitches within the octave with the fingers held rigidly. The same chord can be played at the other six pitches in the octave with the fingers held rigidly in a second position. In the same way, any musical composition can be played with only two different fingerings. This whole-tone connection for the keyboard is well suited to the playing of music written in improved notations. An electrical organ that can play either the diatonic scale or the whole-tone scale on its front digitals was disclosed in 1964 in my U.S. Pat. No. 3,141,371.
For easier learning and playing of music, a good system of music notation makes use of the Guidonian hexachord scale, which is rich in the musical intervals of fifths, fourths, and minor thirds. These intervals are lacking in the whole-tone scale. The hexachord scale is simply the first six tones of the diatonic scale. Musical notation using this six-tone scale allows an intimate relationship between the appearance of written music and the sounds of music. To permit the hexachord notation to be used for instruments without pitch changers, I have devised a system of twelve hexachord key signatures which is very easy to learn and to use when playing.
Even so, my U.S. Pat. No. 3,986,422 describes a hexachord key signature actuator for the keyboard. This can be set to physically actuate any one of the twelve different hexachord key signatures, so that a tonal hexachord scale in that key will be played entirely on the front digitals of the keyboard. At the same time the back digitals will play an associated "chromatic" hexachord based half an octave higher.
The associated "chromatic" hexachord scale on the back digitals is displaced either five or seven digitals to the right of its associated tonal hexachord scale on the keyboard, depending on whether the key signature is written with flats or sharps.
When a six-tone scale is to be played on the front digitals, the diatonic key signature actuator must be disabled by manually setting it to the key of C. Similarly, when the front digitals are to play the diatonic scale it is necessary to manually set the hexachord key signature actuator to the key of c.
For compatibility with the traditional notation, I notate the hexachord scale on two five-line staffs like the treble and bass staffs of traditional notation. Lines representing these staffs are marked on the front digitals of the keyboard. The provision of dual key signature actuators has made it practical for a person trained in the six-tone notation to play music written in the traditional notation. However, the prior key signature actuators and scale changer have added substantially to the cost of the keyboard.
One reason that improved systems of notation and keyboard structures have not been widely adopted is that the amount of music written in any modernized notation is very small compared to the enormous store of musical literature written in the traditional notation, so that a child trained in a modernized notation will at the present time be severely limited if he cannot play music written in the traditional notation. Moreover, teachers are unwilling to train children in a new music system when suitable keyboards are not readily available. Even though a few keyboards exist conforming to an improved notation, they cannot easily be played by people already trained on the traditional keyboard, including the teachers themselves.